Apparatus for the preparation of walled structures



Dec. 24, 1968 D. R. WRIGHT 3,417,429

APPARATUS FOR THE PREPARATION OF WALLED STRUCTURES Filed April 15. 1966 INVENTOR. Dona/c/R. Wrlgfif k/3&2 1M.

United States Patent 3,417,429 APPARATUS FOR THE PREPARATION OF WALLED STRUCTURES Donald R. Wright, Midland, Mich., assignor to The Dow Chemical Company, Midland, Mich., a corporation of Delaware Filed Apr. 15, 1966, Ser. No. 542,927 6 Claims. (Cl. 18-5) ABSTRACT OF THE DISCLOSURE An apparatus is described for the preparation of structures by spiral generation wherein the shape of the structure is controlled by a cam or pattern which controls the position of the material depositing head along a boom or arm. Such cams or patterns may be of the two or three dimensional type.

This invention relates to improved apparatus for the preparation of walled structures by a spiral generation process, and more particularly relates to an improved method and apparatus for obtaining structures having a desired profile or configuration.

U.S. Patent 3,206,899 discloses a walled structure and method for making it. In general, such walled structures are prepared by depositing a material from the material depositing head disposed on the boom which is rotated about a central axis. Successive layers of material are deposited to form a unitary structure. The simplest form of such apparatus is an apparatus which prepares a hemisphere wherein a boom of fixed length is pivoted about a central pivot point and successive layers are deposited until at least a major portion of a hemisphere has been generated. For many applications, a hemispherical arrangement is not desired. For example, it may be desirable that the completed structure has the configuration of a spherical zone of one base having a height substantially less than the radius. Oftentimes, a generally elliptical profile is required, and on occasion, non-circular structures are desirable.

In preparing such a walled structure, it is desirable that the finished building or structure have an outline or configuration which is relatively accurately controlled to desired dimensions. It is also desirable if one apparatus may be used for the preparation of various shaped buildings or structures by the spiral generation technique. It would be beneficial if there were available a light weight flexible, uniform apparatus for the production of walled structures by spirial generation technique which would prepare structures of almost any desired configuration without radical modification of the equipment.

These benefits and other advantages in accordance with the present invention are provided in an apparatus for the production of walled structures by a spiral generation technique wherein the apparatus comprises in cooperative combination a base; the base supporting a base pivot; the base pivot having pivotally afiixed thereto a first elongate element supporting a material depositing head; the elongate element being pivotally connected to the pivot by means of a second pivot, the second pivot having an axis generally normal to the axis of the base pivot thereby permitting rotation of the elongate element about the base and in a plane containing the axis of the pivot so that the elongate element may describe at least a major portion of a solid angle; the elongate element slidably supporting a material depositing head; a cam affixed to the base; a cam follower assembly afiixed to the elongate element; a means to provide proportional linear motion of the material depositing head proportional to the linear displacement of the cam follower relative to the elongate element.

Further features and advantages of the present invention will become more apparent from the following specification taken in connection with the drawing wherein:

FIGURE 1 schematically depicts an apparatus in accordance with the invention constructing a walled structure by the spiral generation technique.

FIGURE 2 schematically illustrates one embodiment of the control mechanism for the apparatus of FIGURE 1.

FIGURE 3 is an alternate base and cam which is utilized with the apparatus of FIGURE 1.

In FIGURE 1 there is schematically depicted a walled structure building apparatus generally depicted by the reference numeral 10. The apparatus 10 is disposed upon a foundation or support 11; the apparatus 10 comprises a base 12; the base 12 has affixed thereto a pivot or stub shaft 13 which extends in a direction generally normal to the plane of the support 11; a template or pattern support 15 is rotatably mounted upon the pivot 13; the template or pattern support 15 has disposed thereon a template, cam or pattern 16; a swivel or pivot bearing 18 for the boom or elongate element is in operative engagement with the pivot 13 and is connected by means not shown to rotate the pattern support 15 as the bearing 18 is rotated about the pivot 13; a second pivot bearing 20 is disposed adjacent the first pivot bearing 18 and is adapted to rotate independently or dependently with respect to the bearing 18 as desired; the bearing 18 has affixed thereto an enlongate operating element or boom 21; the boom 21 has a first end 22 and a second end 23; the first end 22 is pivotally affixed to the bearing 18 by means of a vertical boom pivot 24; the pivot 24 permits pivoting of the elongate element 21 generally parallel to a plane containing the axis of the pivot 13. Thus, the arm 21 is free to move within a solid angle by rotating about both the pivots 13 and 24. Adjacent the second end 22 of the elongate member 21 is supported a motion multiplying means generally designated by the reference numeral 26. The motion multiplying means 26 has a cam follower 27 adapted to engage the surface or edge of the cam 16; the motion multiplying means 26 is in operative communication with the positioner or cable 28 which extends generally adjacent the first end 22 of the boom 21 to the second end 23; the cable 28 has affixed thereto a material depositing head 30 which is moved along the length of the elongate element 21 by means of the cable 28 a distance proportional to the displacement of the cam follower 27; a second or man boom or elongate element 32 is disposed generally adjacent the elongate element 21. The element or man boom 32 has a first end 33 and a second end 34. A support means 35 is slidably disposed on the arm 32. The first end 33 of the arm 32 is pivotally connected to the pivot 20 by means of a pivot 37 which permits motion of the arm 32 in a plane containing the axis of the pivot 13. Thus, the second arm 32 is capable of describing a solid angle in the manner generally similar to the arm 21. The support means 35 is particularly suited and adapted to carry a workman and be maintained in selected spaced relationship from the material depositing head 30. A walled structure portion 38 is shown which has been prepared by the apparatus 10.

Operation of the apparatus of FIGURE 1 is generally similar to operation of the apparatus of US. 3,206,899 insofar as the deposition of the structural material is concerned. However, the position of the material depositing head in the present invention is controlled by means of the cam 16 in combination with the motion multiplying means 26, thereby permitting one apparatus to prepare a wide variety of structural configurations. The second elongate element 32 is particularly beneficial when erecting large structures, as it may be maintained in spaced relationship to the first elongate element or boom 21 and a workman can control and adjust the material deposition head and/or feed strips of material thereto. Beneficially, the support 35 can traverse the second elongate element in a manner proportional to the movement of the material depositing head 30 and yet be driven about the central pivot by the head 30 without providing a significant load thereon.

In FIGURE 2 there is schematically represented a motion multiplying means suitable for use with the apparatus of FIGURE 1. The motion multiplying means is generally designated by the reference numeral and comprises in cooperative combination a reversible electrical motor 41 having a first out-put shaft 42 and a second output shaft 43; the first output 42 is in operative engagement with the gear reducer 44; the gear reducer 44 carries a pulley 45 which is in operative communication with the second pulley 46 by means of a belt or power transmission means 47; the pulley 46 is in operative communication with an extensible assembly 48 comprising a housing 49 having disposed therein an externally threaded element or lead screw 50. The lead screw 50 is in operative engagement with an extensible arm 52. The extensible arm 52 has a terminal end 53 remotely disposed from the housing 49. A cam follower 54 is connected to the end 53 of the arm 52. The cam follower 54 comprises a first electrical switch 55 and a second electrical switch 56. The switch 55 has a cam engaging and switch actuating member 57, whereas the switch 56 has a cam engaging and switch actuating member 58. A power source 59 is in operative communication with the motor 41 by means of a first lead 60 and a second lead 61 which goes to a common pole of the switches 55 and 56, the opposite pole of the switches 55 and 56 is connected with the reversible motor 41 by means of the leads 63 and 64. A cam 67 is disposed adjacent the switch elements 57 and 58. The cam 67 has a model or pattern surface 68. A second gear reducer is coupled to the shaft 43 of the motor 41. The gear reducer 70 has a first output shaft 71 and a second output shaft 72. A pulley 73 is rigidly aflixed to the shaft 71, a flexible shaft 75 is secured to the shaft 72. An endless cable or loop 77 passes about the periphery of the pulley 73 and a remotely disposed pulley 78. A foam depositing head 80 is rigidly afiixed to the cable 77. A second pulley 81 is in operative connection with the shaft 75. An endless cable or loop 83 passes about the periphery of the pulley 81 and a second pulley 84; a man cage or worker support 85 is connected to the loop 83.

In operation of the control system set forth in FIGURE 2, the motion multiplying means 40 is mounted to an arm such as the arm 21 carrying the material depositing head while the assembly comprising the pulleys 81 and 84 and loop 83 is mounted to the arm 32. By selecting suitable gear ratios for the gear reducers 44 and 70, a desired rate of travel of the foam depositing head 80 is obtained. The cam 67 is positioned generally as the cam 16 of the apparatus of FIGURE 1. The switches 55 and 56 are positioned in such a way that movement of the boom causes one or the other of the switches to close and drive the motor 41 in the appropriate direction to maintain the switch activating elements 57 and 58 at a position wherein the motor is not energized, that is, the switch elements are adjusted to provide a small dead spot to prevent undesired hunting. Thus, as the arm supporting the cam follower is moved relative to the cam, the motor 41 through the shaft 42 to the gear reducer 44 and the drive train consisting of pulleys 45, 46 and the belt 47 maintain the switches in relatively fixed distance from the surface of the cam. By means of the output shaft 43, the gear reducers 70, the pulley 73 and the loop 77, the depositing head 80 is positioned or moved a distance which corresponds to a distance proportional to the configuration of the cam. Thus, as the arm such as the arm 21 is raised in a vertical direction, the foam depositing head such as the head 80 or the head 30 traces a curve corresponding to an enlargement of the cam surface. Utilizing a planar cam such as is shown in FIGURES 1 and 2, the cam is required to rotate about the pivot 13 with the arm 21.

In FIGURE 3, there is depicted an alternate modification of the present invention generally depicted by the reference numeral 90. The modification comprises a fixed base 91, a pivot 92 corresponding to the pivot 13 of FIGURE 1 and a three dimensional model 93 of a desired surface to be generated. First and second pivot bearings 94 and 95 are rotatably afiixed to the pivot 92; first and second arms 96 and 97 corresponding to the arms 21 and 32 are afiixed to the bearings 94 and 95, respectively. A cam follower 98 is in contact with a surface 99 of the three dimensional model 93.

In operation with the device of FIGURE 3, the base and the model surface 99 or cam are rigidly affixed and do not rotate. As the arms 96 and 97 rotate about the pivot 92, the cam follower 98 causes a foam depositing head to be positioned a distance along the boom proportional to the configuration of the surface 99. By employing a three dimensional cam or pattern such as the model 93, the configuration or structure which can be prepared is primarily limited only by the versatility of the material depositing head.

As is apparent from the foregoing specification, the present invention is susceptible of being embodied with various alterations and modifications which may differ particularly from those that have been described in the preceding specification and description. For this reason, it is to be fully understood that all of the foregoing is intended to be merely illustrative and is not to be construed or interpreted as being restrictive or otherwise limiting of the present invention, excepting as it is set forth and defined in the hereto-appended claims.

I claim: 1. An apparatus for the production of walled structures by a spiral generation technique wherein the apparatus comprises in cooperative combination:

a base; the base supporting a pivot; the pivot having pivotally affixed thereto a first elongate element supporting a material depositing head;

the elongate element pivotally connected to the pivot by means of a second pivot; the second pivot having an axis generally normal to the axis of the base pivot thereby permitting rotation of the elongate element about the base and in a plane containing the axis of the pivot so that the elongate element may describe a major portion of a solid angle;

the elongate element slidably supporting a material depositing head;

a cam atfixed to the base;

a cam follower assembly aifixed to the elongate element;

means to provide proportional linear motion to the ma terial depositing head along the first elongate element proportional to the linear displacement of the cam follower relative to the elongate element.

2. The apparatus of claim 1 wherein the cam rotates 5 6 about the base pivot in fixed relationship to the elongate References Cited 5 t f 1 1 h th th UNITED STATES PATENTS e appara us 0 c aim W erem e cam is a ree dimensional cam and is fixed relative to the base pivot. 5511 i;

4. The apparatus of claim 1 wherein a second pivoted 5 2607100 8/1952 Urschel 25 131 elongate element is disposed generally adjacent the elon- 2877530 3/1959 Winn X gate element bearing the material depositing head. 3:206:899 9 /1965 Wright 25 131 X 5. The apparatus of claim 4 wherein a support means is slidably disposed on a second elongate element. SPENCER OVERHOLSER, Primary Examiner- 6. The apparatus of claim 5 wherein the support means 10 JONES, Assistant Examiner is in operative communication with means to position the support means as the material depositing head is posi- Cl- X-R. tioned. 2513l; 26434 

